Sean-Paul Correll, a security researcher a Panda Security, explains that under its latest guise, scareware scams appear as spam messages sent to personal Skype accounts.

The message poses as originating from an account called "Online Notification" and claims to have discovered infection on a supposedly compromised PC. Once the prospective mark visits the linked site for "more information", a fake antivirus scan takes place that warns a system is crawling with malware in a bid to coerce potentially alarmed users into buying a clean-up utility of no value.

"Rogueware distributors are like the cockroaches of the Internet; they’re everywhere," Correll notes.

One strain of scareware detected by Panda disables all applications on a compromised PC except the rogueware utility and IE. A browser is left available because it's needed for a victim to hand over payment to rogues. After receiving funds, the full version of the scareware package reactivates disabled applications.

Black hat SEO tactics remain the main tactic for seeding scareware traps. Typically, a topical subject is exploited as a theme before a mainstream website is attacked and multiple links on related subjects are posted. The ruse is designed to propel the targeted site up the rankings in Google's index for the term.

Surfers who follow tainted search results onto a compromised site are redirected to scareware download sites, but only if they are referred from Google. Computer users who visit a compromised site directly will not be redirected.

Google has established a custom search page - www.anti-malvertising.com - designed to assist customers of ad networks to uncover possible attempts to distribute malware through advertising, a concern highlighted by the recent New York Times rogueware attack. Security researchers from the search engine have also become active participants in closed mailing lists discussing scareware and the wider cybercrime problem.